Suspension arrangement for a compacting work machine

ABSTRACT

A suspension arrangement is provided for a compacting drum of a compacting work machine. First and second suspension members connect first and second ends of the compacting drum to a frame of the work machine. The first and second suspension members allow the first and second ends of the compacting drum to oscillate through an angle α about a horizontal axis relative to the frame.

TECHNICAL FIELD

[0001] The invention relates generally to compacting work machines and more particularly to a drum suspension arrangement for a compacting work machine having improved ride and steering capability.

BACKGROUND

[0002] Compacting work machines are commonly employed for compacting freshly laid bituminous mixtures or asphalt, soil, and other compactable materials or substrates. For example these work machines may include plate type compactors or rolling drum compactors with one or more drums. The drum type work machines function to compact the material over which the machine is driven. In order to more efficiently compact the material the drum assembly often includes a vibratory mechanism for inducing vibratory forces on the material being compacted.

[0003] It is common practice in the compacting of asphalt to use work machines that includes two rotating drums to more efficiently compact the material. This is so that during each pass over the material being compacted each drum performs a portion of the compacting process. These double drum compactors either have an articulating frame or each drum has the ability to pivot about a vertical axis so that the work machine can be steered in a desired direction during operation. It is desirable to keep both drums in contact with the road surface. To accomplish this over rough terrain, an oscillation axis, us of an equalizer pin or other equalizer mechanism is added to the frame. During tight turning operations, with an articulated frame machine, the weight in the center of the machine causes uneven weight distribution across the width of the drum. When an oscillation axis is added to the articulated frame, the uneven weight distribution is only on the drum, but the magnitude of the uneven distribution is doubled. At times, during a tight turn, depending on how much weight is in the machine the inside portion of one drum can actually lift off of the material being compacted. This is contrary to the goal of finishing a smooth flat road surface.

[0004] Previous attempts to solve this problem have included limiting the turning radius and distributing weight over the ends of the machine. These situations are contrary to the goals of the machine to have good maneuverability and compacting close to objects in front or behind the machine.

[0005] The present invention is directed at overcoming one or more of the problems as set forth above.

SUMMARY OF THE INVENTION

[0006] In one aspect of the present invention, a suspension arrangement is provided for a compacting work machine having a frame. The suspension arrangement includes a drum having first and second ends. The drum defines a horizontal axis. A first suspension member connects the first end of the drum member to the frame and a second suspension member connects the second end of the drum member to the frame. The first and second suspension members allows each of the first and second ends of the drum member to oscillate about the horizontal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a diagrammatic side elevational view of a work machine embodying the present invention;

[0008]FIG. 2 shows an axial cross section view taken along line 2-2 through a compacting drum of the work machine of FIG. 1 embodying the present invention; and

[0009]FIG. 3 is a diagrammatic front view of a compacting drum embodying the present invention.

DETAILED DESCRIPTION

[0010] A compacting work machine 10, for increasing the density of a compactable material 12 or mat such as soil, gravel, or bituminous mixtures, an example of which is shown in FIG. 1. The compacting work machine 10 is shown as being a double drum vibratory compactor. A first compacting drum 14 and a second compacting drum 16 are rotatably mounted to and support a machine frame 18 of the compacting work machine 10. The machine frame 18 includes a first frame 20 that supports an operator's station 22 and a second frame 24 that supports an engine 26. The first and second frames 20,24 are pivotally coupled together by an articulating hitch 28. The articulating hitch 28 is used to steer the work machine 10 by way of a fluid cylinder not shown in a known manner. It should be noted that the hitch 28 is only capable of articulating about a vertical axis 29 and no other movement. Connected to the engine 26 are a first and a second power source 30,32 conventionally connected thereto. Variable displacement fluid pumps or electrical generators can be used as interchangeable alternatives for the first and second power sources 30,32 without departing from the present invention.

[0011] Referring now to FIG. 2, the first compacting drum 14 includes an exemplary vibratory mechanism 34 that is operatively connected to a first motor 36 via a universal connecting shaft 38. The first motor 36 is operatively connected, as by fluid conduits and control valves or electrical conductors neither of which are shown, to the first power source 30. The first motor 36 supplies rotational motion to the vibratory mechanism 34 in a known manner so as to impart a vibratory force through the first compacting drum 14 to the compactable material 12. It should be understood that the first and second compacting drums 14,16 could have more than one vibratory mechanism per drum.

[0012] In as much as, the first and second compacting drums 14,16 and the first and second frames 20,24 are structurally and operatively similar. The description, construction and elements comprising the first compacting drum 14 and the first frame 20, which will now be discussed in detail and as shown in FIG. 2, applies equally to the second compacting drum 16 and the second frame 24 with like element numbers representing similar components.

[0013] A yoke portion 40 extends downward at the outward most portion of the first frame 20. Yoke portion 40 is a bifurcated member that extends downward on the outside of compacting drum 14. A housing of a propel motor 42 is connected to one side of the yoke portion 40 as by fasteners. Propel motor 42 is positioned to extend inwardly into a cavity 44 through a bulkhead 46 in a first end 50 of the drum 14. A mounting plate 52 is connected in a conventional manner to an output 54 of the propel motor 42. A first suspension member 60 is connected to the mounting plate 52 as by fasteners. Propel motor 42 in turn is connected as by fluid lines or electrical conductors to the second power source 32. Thus, the first suspension member 60 is connected to the yoke portion 40 of the first frame 20 and rotatably supports the first end 50 of the compacting drum 14. When the first power source 30 supplies energy to the propel motor 42 rotational force is exerted on the compacting drum 14 so as to propel the compacting work machine 10 in a desired direction and speed.

[0014] A second suspension member 62 is connected, as by fasteners, to a mounting plate 64 that is rotatably connected to the other side of the yoke portion 40. The second suspension member 62 in turn is connected in a known manner to a bulkhead 66 on a second end 68 of the first compacting drum 14. Thus, the second suspension member 62 is connected to the yoke portion 40 of the frame 22 and rotatably supports the second end 68 of the compacting drum 14. The first and second suspension members 60,62 vibrationally isolate the compacting drum 14 from the first frame 20.

[0015] Still referring to FIG. 2, the first and second suspension members 60,62 are shown as being rubber isolation mounts 72. However it should be understood that the first and second suspension members 60,62 could be springs, fluid dampening members, or any other suspension member capable of supporting the weight of work machine 10 without departing from the gist of the present invention. Actually, the first and second suspension members 60,62 include a plurality of first and second suspension members 70,72. The first and second suspension members 60,62 are for example sandwich type vibration mounts, such as those offered by the Lord Corporation with durometer rating of 55. Thus, a suspension arrangement 74 is provided for the compacting drum 14 from the machine frame 18.

[0016] Referring now to FIGS. 2 and 3, drum 14 defines a horizontal axis 74 that extends from the first end 50 to the second end 68 thereof. The first and second suspension members 60,62 isolate the vibrational forces from the vibratory mechanism 32 from the rest of the compacting work machine 10 as described above. Additionally, the first and second suspension members 60,62 allow each of the first and second ends 50,68 of the compacting drum 14 to oscillate or pivotally move through an arc or angle α. As seen in FIG. 3, angle α is shown exaggerated but as an example is in the range of plus or minus 10° from a horizontal position. It has been found that there are advantages for the angle α to be in the range of plus or minus 2.5° from a horizontal position.

[0017] Industrial Applicability

[0018] In operation, the suspension arrangement 74 described above provides suspension for the first and second compacting drums 14,16 that improves the ride for an operator and enhances steering capability. For example, when the compacting work machine 10 is maneuvered through a right turn, the weight of the machine 10 tends to list to the left, the first suspension member 60 will flex or compress and the second suspension member 62 will flex or extend. With the suspension arrangement 74 the weight shift of the work machine 10 still occurs but is one half of a machine with an oscillation joint. In this manner the compacting drum 14,16 maintains contact with the surface or mat 12 being compacted, as opposed to a full shift of the weight from the second end 68 of the compacting drum 14,16 and possibly even lifting the second end 68 from the mat 12.

[0019] Additionally, as the compacting work machine encounters disparities in the surface being compacted, such as elevational differences between the first and second ends 50,68 of the compacting drum 14,16. The first and second suspension members 60,62 are allowed to flex either compressing or extending to compensate for the elevational disparities much like an independent suspension.

[0020] Thus, a suspension arrangement 74 is provided that allows the compacting work machine 10 to utilize a simple articulating hitch 28 that does not require oscillation capability. The suspension arrangement 74 reduces the weight imbalance on the compacting drum 14,16, reduces the complexity of the hitch 28, and reduces the weight and cost of the overall work machine 10. 

What is claimed is:
 1. A suspension arrangement for a compacting work machine having a frame, said suspension arrangement comprising: a drum having first and second ends, said drum defining a horizontal axis; a first suspension member connecting said first end of said drum to said frame; a second suspension member connecting said second end of said drum to said frame; and said first and second suspension members allowing each of said first and second ends of said drum to oscillate through an angle α about the horizontal axis relative to the frame.
 2. The suspension arrangement of claim 1, wherein the angle α is in the range of plus or minus 10 degrees.
 3. The suspension arrangement of claim 2, wherein the angle α is in the range of plus or minus 2.5 degrees.
 4. The suspension arrangement of claim 1, including a plurality of suspension members connecting said first end of said drum to said frame and a plurality of suspension members connecting said second end of said drum to said frame.
 5. The suspension arrangement of claim 4, wherein each of said plurality of suspension members is a rubber mount.
 6. A work machine, comprising: a first frame; a second frame; an articulating hitch pivotally connecting said first frame to said second frame; and a suspension arrangement as set forth in claim
 1. 7. The work machine of claim 6, wherein said articulating hitch defines pivotal movement only about a vertical axis.
 8. A work machine for compacting a compactable material, said work machine comprising: a first frame; a second frame; an articulating hitch pivotally connecting said first frame to said second frame; a first drum defining a horizontal axis; a first pair of suspension members connecting said first drum to said first frame; a second drum defining a horizontal axis; a second pair of suspension members connecting said second drum to said second frame; and said first and second pair of suspension members allowing each of said first and second drums to oscillate through an angle α about the horizontal axis relative to the first and second frames.
 9. The work machine of claim 8, wherein said articulating hitch defines pivotal movement only about a vertical axis.
 10. The work machine of claim 8, wherein the angle α is in the range of plus or minus 10 degrees.
 11. The work machine of claim 10, wherein the angle α is in the range of plus or minus 2.5 degrees.
 12. The work machine of claim 8, including a plurality of suspension members connecting said first drum to said first frame and a plurality of suspension members connecting said second drum to said second frame.
 13. The work machine of claim 8, wherein each of said plurality of suspension members is a rubber mount. 